Embodiments of the present invention relate to a method of forming a photoresist burr edge and a method of manufacturing an array substrate.
Thin film transistor liquid crystal displays (TFT-LCDs) possess advantages of small volume, low power consumption, low radiation, etc., and are gradually prevailing in the market of flat plate displays. As for a TFT-LCD, an array substrate and the manufacturing method thereof control, to a large extent, the performance, yield, and price of the final products. In order to efficiently reduce the production cost of TFT-LCDs and improve the production yield thereof, the manufacturing process of a TFT-LCD array substrate is gradually simplified. Such manufacturing processes have been evolving from initial 7-mask processes to current 4-mask processes based on the slit photolithography technology. In addition, 3-mask processes are under research and development.
One 3-mask process has been proposed in Chinese patent application CN 200510132423.X, in which a gate line and a gate electrode are formed through a patterning process with a first normal mask; a data line, a source electrode, a drain electrode, and a thin film transistor (TFT) channel region are then formed through a patterning process with a second gray tone mask; and a pixel electrode is finally formed through a patterning process with a third normal mask. In this method, a normal mask is employed in the third patterning process, the sidewalls of the photoresist pattern formed by exposing and developing have a vertical topography, and the sidewalls of the passivation layer have an inwardly concaved topography with over-etching during the etching process, so that the transparent conductive thin film to be deposited subsequently is disconnected at the sidewalls of the passivation layer. However, in practice, such process requires applying a relatively thick photoresist layer to make the slope of the photoresist edge as steep as possible and preferably close to 90 degree. Unfortunately, such method practically cannot appropriately render the transparent conductive thin film disconnected at the photoresist edges. As a result, the manufacturing cost is increased, and the quality of a lifting-off process cannot be ensured. As for the TFT-LCD array substrate in preparation, any adhesion to the underlying layer of the transparent conductive thin film results in certain residual, which brings great harm to the lifting-off process and gives rise to defects to be overcome of the 3-Mask process.